Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
Check out the new SourceForge HTML5 internet speed test! No Flash necessary and runs on all devices. ×

Comment Re:"the free blah blah blah of space" (Score 1) 209

...we're likely to need robots on the Moon to extract rocket fuel from the polar regolith

There are any number of places to get rocket fuel in the solar system: water from comets, or the polar regions of the Moon or Mars, or just go straight to Mars and synthesize CO and O2 straight from the Martian atmosphere using nuclear reactors. Which place ends up being most attractive is going to be highly dependent on the capabilities and needs of the launch industry - if everything converges around methane (which it's looking to do, at least based on SpaceX and Blue Origin's exploration-class vehicles) then that works nicely with Mars, assuming you bring some hydrogen with you at first and then move on towards getting it from the poles or the rumored subsurface supplies. The moon is one good option, but it's not by any means a given that we'll have to go there first.

In short, you need that supply chain. Or you need to hump every kilo of that material from Earth to your first industrial site and then build your supply chain.

I agree with this. Once we get serious about space, the absolute top priority will be building up that supply infrastructure - and if we can make LEO cheap and routine, I think that will happen pretty fast.

Comment At least one organization is doing some of this... (Score 1) 536

Living Goods is a pretty cool charity that I just started supporting recently. They focus on educating and equipping community health workers that sell basic health and sanitation products in impoverished regions. It's pretty awesome, actually - the health workers fund themselves by selling these products, it grows the local economy by creating jobs, it spreads information and supplies to stop the spread of avoidable disease.

The tech comes in because they've developed an app that assists in diagnosis of common, treatable ailments, and provides info and scheduling about checkups on prenatal care, all of which can have a big impact on health. Also, they've actually run some randomized trials that have shown something like a 30% reduction in infant mortality in communities that are served by this charity, which also qualifies as a "nerdy" IMO because many charities are driven by ideology and dogma and aren't interested in gathering quantifiable evidence that their services actually make a difference.

If you want to check them out: https://livinggoods.org/what-w...

I'm not affiliated with them except that I recently became a donor. I thought their approach was truly unique in the world of charitable giving.

Comment Re:"the free blah blah blah of space" (Score 1) 209

But I would think that the process of developing then necessary technologies in good time to deploy them if needed, is a fairly good investment.

I agree, but I think that can be a separate effort - making infrastructure projects more difficult/expensive than they have to be just to learn some things about asteroid relocation is going to be a worse solution IMO than making them distinct efforts - efficient asteroid mining, and efficient asteroid redirection.

Lets look at some numbers. If you can fit a single astronaut into a sphere 1.5m in diameter without them going insane (note the "if" - as a caver (EN_US: spelunker], I'd find a week in a 1.5m chamber wearing.

What I envision is something like an emergency bunker that is just large enough to fit the whole crew, and surrounded by some combination of fuel tanks, water supply, waste, and other massive materials that you'll be bringing with you anyway. This can provide pretty adequate shielding without much extra mass, but as you point out, it's going to be cramped. For that reason I would classify this as a short-term solution that is tolerable for exploration missions (and much better than the Apollo crews had) but not for sustained habitation. That's why I contend that we need orbiting manned facilities to be in LEO until we can afford the mass to shield large portions of a station. Which won't really happen IMO until we are mining asteroids.

Comment Re:"the free blah blah blah of space" (Score 1) 209

The papers are not about performing human spaceflight. They're about building the space-based infrastructure that would allow human space flight at a negligible cost, while simultaneously building power stations for Earth, possibly compute-stations for Earth.

I would contend that most of that infrastructure has a better place to be than lunar orbit. For solar power - GEO is going to make the most sense for transmitting power to the ground, if it's providing power to somewhere in space, then co-locate it with whatever you care about. For harvesting asteroids - the equipment will be much lighter and more portable than the asteroids, so move the equipment to the asteroid's existing orbit. Earth mining operations process as much material as possible on-site, for the exact same reasons. You don't want to spend money transporting stuff that you're going to discard. For anything human related, you want to be in LEO (and protected by the magnetosphere) unless you have something specific to do, and then go where the job is.

So the point is that lunar orbit, L1, L2 might be attractive as pit stops, but there's little to recommend those locations other than being on the way to somewhere you care about. Getting there is a lot more expensive and less protected than LEO, less useful to Earth than GEO, and if you want resources just move the operation to the asteroid, don't move the asteroid and the mining equipment to an arbitrary third location.

There is a physically-possible plan for solving either plan that doesn't involve large amounts of mass? Enlighten me!

What I mean there is that you can solve either problem pretty cheaply in the short term - in terms of radiation, just choose to tolerate the risk, and/or bring a tiny shielded rad bunker that the astronauts can duck into in a pinch. For gravity, just accept the bone loss as the price of doing business, and/or have your astronauts do hours of exercise a day to try to mitigate the effects. Long term solutions are thick, heavy shielding (whether EM or just dumb mass) and a large centrifugal system.

Comment Re:"the free blah blah blah of space" (Score 1) 209

Being near the moon doesn't seem to me immediately better than any other place in orbit, and in many ways worse. If you want to mine regolith, just plant your colony on the surface. If you want to be close to Earth, LEO is closer and you get radiation protection from the magnetosphere. If you want to mine asteroids, go to where they are, or bring them to LEO. If you want something planet-like, Mars has more resources that are easier to use (ice, plenty of carbon readily accessible in the atmosphere).

I know people get excited about L1 and L2 and low-energy transfers, but that only works if you're willing to wait years to get to your destination - which isn't going to make sense for human spaceflight, at least until we can reliably solve the gravity and radiation issues, both of which are only solved long-term with lots of mass.

Comment Statistical analysis demonstrated this long ago... (Score 5, Informative) 305

Back in the 70's and 80's, people recorded dolphin vocalizations, and identified the equivalent of human phonemes, basically just different sound patterns that would occur repeatedly. By collecting a lot of data, and counting up the occurrences of distinct phonemes, they were able to show a phoneme frequency that matches the exact same patterns as human speech (frequency here meaning how often a phoneme occurs, not the frequency of the sound waves).

For instance, "the" occurred 6 times in the paragraph above, "and" occurs 3 times, and words like "vocalization" occur once - far less often. All human languages have this distribution where a small quantity of words makes up the bulk of common conversation, whereas things like bird calls or other vocalizations from less intelligent species follow a more flat distribution.

The point being, we've known for a long time that dolphins communicate using something very similar to human speech. This is pretty neat progress, but IMO it's pretty disheartening that after several decades we're still not anywhere near understanding their language. If we can't figure out how to communicate with fellow mammals sharing a common lineage, it really challenges the common sci-fi trope of having any kind of meaningful discourse with a creature from the other side of the galaxy.

Comment Re:Dumping the Headphone Jack: My Theory (Score 3, Interesting) 551

The 3.5mm standard may not be established in an ISO document somewhere, but in a practical sense it's as reliable a standard as you're likely to find. I've had lots of problems with Micro-USB, for instance - some cables fit in snugly, some fit loosely, etc. But I've never had a 3.5mm connection fail, and they are so simple and ubiquitous that they have allowed some neat third-party hardware (think Square payment systems). That's not the kind of thing you can roll out without a solid standard in place (either formal or de facto).

The standard has been just fine for all previous generations of iPhone, and for other Apple hardware as well. This is just a money grab, and it's going to lead to new and needless complexity in one of the very few technology interfaces that had remained pretty foolproof.

Comment A bunch of cynics... (Score 1) 73

Am I the only one to think this sounds like a badass way to trial various technologies for space colonization? A substantial amount of the ECLSS tech will be transferable, for starters. I get that everyone wants to be suspicious of China all the time, but they are serious about their space program, and this gives them a chance to be the first to create a continual human presence in a deep-sea habitat. Pretty cool IMO.

Comment Re:hare brained "skepticism" (Score 1) 532

Perpetual motion cannot be proven to be impossible.

Well, you can't prove that there are no invisible pink unicorns. That doesn't mean that we should believe in invisible pink unicorns. Proving a phenomenon impossible in a strict sense is, itself, impossible. That said, with perpetual motion, we're about as close to a proof as you can get - conservation of energy has been tested and confirmed in a million different ways both experimentally and observationally, and if conservation of energy is a valid priniciple, perpetual motion is expressly prohibited. What's more, people have been working on perpetual motion machines for centuries, and not a single example has ever withstood scrutiny.


In fact it appears to exist, just to not be (directly) useful.

Citation needed. Nobody credible is calling virtual particles perpetual motion. And what I'm talking about (and what OP was talking about) is a machine that generates infinite energy - such a thing is entirely impossible, and any trained physicist or engineer will dismiss it outright because it's a fantasy and completely contradicts many of our most useful, fundamental, and well-verified principles in physics.

Comment Re:hare brained "skepticism" (Score 1) 532

I was agreeing with you in principle until this:

You wouldn't actually use a set of these things to push a fucking rocket around space, morons. You would put a set of these things around an axis like a chinese fire wheel, and allow their greater than 100% efficiency to spin them around the axis producing a limitless energy production in the zero gravity.

This is why we need skepticism. Because this is precisely backwards - if the EM Drive can do that, then the entire universe breaks. 1+1 = 17 and conservation of energy goes away. Centuries of physics gets tossed into the shredder.

On the other hand, if the EM Drive can produce small but consistent levels of thrust without using propellant, and do it in a way that doesn't break conservation of energy, then it is completely useful for space travel, and could open up space travel in a huge way, but still operate within reasonable constraints. We update the models, maybe finally make some progress on unifying quantum mechanics and relativity, and have a nifty new effect to start playing with.

The thing is, as soon as you say with a straight face that something is "limitless", you've left the realm of science and entered fantasy land. We need dreamers, but we also need people who will take the 10 minutes of wikipedia reading needed to understand the laws of thermodynamics, and use filters to separate the implausible ideas (propellant-less propulsion) from the laughable ones (infinite energy machines). A refusal to accept perpetual motion machines (like what you describe) isn't even skepticism - it's just common sense for anybody who has developed a cursory understanding of physics.

Comment Re:Obligatory Pentax Fanboy Comment (Score 1) 160

I think you must work a dance hall very differently than I would, based on your focal length. I'm generally at 35mm or wider (on APS-C) so I'm pretty close and mixed in among the action. In that context, if I have a need for flash (which means the house lights are way down and the DJ has some effects going) then it inherently blends into the existing atmosphere of pulsing music and strobing lights. Ceremonies I shoot almost exclusively with ambient lighting because that's a quiet, subdued event where I don't want to attract attention, but at a reception I'm one dude in the mix of a bunch of dancers, adding a little bit of light to the situation isn't likely to be a problem.

In that context, flash is about as far from "samey" as you can get, IMO. For some examples, ambient lighting at receptions often gets you results like this: http://stevewatkinsphotography...
or this: http://static.photo.net/attach...
While flash gets you images more along the lines of this: http://www.melissajill.com/ima...
or this: http://static.jasminestar.com/...

Flash gets you brighter colors, sharper details, and most importantly, control over the situation - if you MUST get a shot at a precise moment, and don't know what the lighting is or how cooperative your subject is going to be (think cutting cake, bouquet toss, etc) then I find you don't have the privilege of setting up your focus point in advance and waiting for the subject to cooperate - eyes might be closed, subject might move in the opposite direction than you predict, or whatever. You can also line up an off camera flash for a cool effect, change your setup throughout the evening for variety, etc... So you proactively move focus and lighting to where the action is and where you need to be.

So, honestly, I would bet that a portrait lens with ambient lighting is the last thing most photographers would want for a dance or reception, except for a couple niche cases like the slow dances (father/daughter, etc) and maybe toasts - everything with action in it will probably come out better with a wider lens and flash. Of course, some of the most creative shots can come from breaking the standard rules, but to get back to the original point I think a 50/1.4 or 35/2.0 is going to be plenty fast to shoot a reception competently with a modern DSLR that can do decent ISO. If that setup can't get you your shot, your photography will be improved more by $1000 worth of flash gear than the >>$1000 you'll be spending to get a lens that only offers another fraction of a stop in speed.

Comment Re:Obligatory Pentax Fanboy Comment (Score 1) 160

Well, if you're trying to keep shutter speed high, I can see the need for that. I've shot plenty of wedding receptions that are painfully dark though - and the majority of the time, the best answer is just off-camera flash, or bounce flash if the situation is right. I'm mainly saying that because a lot of times the camera is physically capable of focusing and I could, in-principle, crank up the ISO and shoot without extra lighting, but in situations like that your colors are so muted and there's so little dynamic range in the lighting environment that the pictures that come out are flat and drab, or schizophrenic and nonsensical depending on the DJ's lighting setup.

Much better to have an off-camera flash or two, slow that shutter down enough to get a hint of motion blur and ambient lighting, but rely on the flash to keep the subject nice and sharp. Some of those scenarios really have been so dark though that I can't actually see well enough to compose a shot very well (I can tell that people are dancing, but can't see expressions, etc) so it really is a "shot in the dark". Thankfully, I still often manage to get some fun expressions and positions. ;)

Everybody has their own style, but for myself I find that all my favorite dark reception hall shots are made with a setup along those lines - and honestly, the wide aperture is more of a hazard than a benefit so I find myself at 4.0 as often as not, because things are moving so fast that getting a razor-thin DOF dialed in exactly where you want it is next to impossible. The off-camera lighting provides the drama and subject isolation that you usually rely on bokeh for.

Comment Re:Obligatory Pentax Fanboy Comment (Score 1) 160

Even with the high iso capabilities of modern dslr's, I've still found situations (not at weddings) where the f/1.4 on my 50mm and 85mm lenses hasn't quite done the job to my liking.

Really? I have a tough time imagining that situation. If you need f/1.4 and ISO 12800 (any modern DSLR should be able to do this passably) things can be so dark that it becomes difficult to compose a shot because you simply can't see. At that point the camera system is rivaling or exceeding the capability of human night vision. That becomes "good enough" in my book, because even if I could get noiseless, focused images with f/1.2 and ISO 52800, I'd just be pointing and clicking in random directions in a pitch black room.

Comment Re:Obligatory Pentax Fanboy Comment (Score 1) 160

My wife is a photographer and I'm her second shooter for weddings - we've got Pentax K-5 bodies (APS-C) and yep, a 17-70mm/4.0 is my workhorse, which translates about the same. She tends to use the 16-50mm/2.8, which is decent but honestly her and I both prefer to have a backup body with a prime. The humble 50mm/1.4 actually does really well, I also really love the FA Limited 31mm/1.8 and the 35mm/2.0 (the best $300 we ever spent on photo gear).

I honestly never feel like there's something I want to do in the context of wedding photography that I don't have a lens for... except maybe that Nikon 200mm/2.0. If I had unlimited cash, that one might convince me to switch brands. But even then, a lot of those exotic lenses end up being gimmicky for wedding work - you use it for a shot or two, but it's too specialized for most situations. After getting the basic fast primes and fast-ish zooms, we really just rent specialty lenses here and there but haven't found any worth owning.

Since we actually try to make some money on this endeavor, we are pretty practical about gear choices. Better to have multiple last-gen camera bodies that can take a beating and provide redundancy than the latest whiz-bang camera that will depreciate like crazy. So I imagine we'll make the jump to the K-1 in a year or two, but at that point there will be an investment in longer lenses as well to account for the changeover from cropped sensor. Digital camera bodies became "good enough" for 99% of wedding situations about 3 years ago, so at this point the extra expenditure for upgrades is hard to justify.

Slashdot Top Deals

"It doesn't much signify whom one marries for one is sure to find out next morning it was someone else." -- Rogers